Convergent evolution with combinatorial peptides

Once the sequence of a genome is in hand, understanding the function of its encoded proteins becomes a task of paramount importance, Much like the bio chemists who first outlined different biochemical pathways, many genomic sc ientists are engaged in determining which proteins interact with which prot eins, thereby establishing a protein interaction network, While these inter actions have evolved in regard to their specificity, affinity and cellular function over billions of years, it is possible in the laboratory to isolat e peptides from combinatorial libraries that bind to the same proteins with similar specificity, affinity and primary structures, which resemble those of the natural interacting proteins. We have termed this phenomenon 'conve rgent evolution'. In this review, we highlight various examples of converge nt evolution that have been uncovered in experiments dissecting protein-pro tein interactions with combinatorial peptides, Thus, a fruitful approach fo r mapping protein-protein interactions is to isolate peptide ligands to a t arget protein and identify candidate interacting proteins in a sequenced ge nome by computer analysis, (C) 2000 Federation of European Biochemical Soci eties. Published by Elsevier Science B.V, All rights reserved.